Consider a favorite cause of the sustainability movement: locavorism. Champions of “sustainability” assert that, because local foods don’t have to be shipped very far to their final consumers, such foods are more “sustainable” than are foods grown and raised at great distances from where they are consumed.

This analysis appears sound to people who are blind to all but the resources used to transport foods from farms to dining tables. Yet transportation consumes only a small portion of the resources required to feed us. Labor, fuel, water, irrigation equipment, tractors and other farm tools, fertilizers, pesticides, packaging and (of course) land must also be used.

What effect would eating only locally grown foods have on the use of these other resources? Locavores seldom ask this question.

Fortunately, this question has been asked by sensible economists. In their splendid 2012 book, “The Locavore’s Dilemma,” Pierre Desrochers and Hiroko Shimizu conclude that the ecologically and economically best diet is one with foods from all across the globe. Among the most important reasons is that the amount of resources required to eat only locally grown foods would be stupendous.

UPDATE: To make explicit a point that I assumed was obvious if only implicit in the above passage, I would amend the last-quoted sentence to read:

Among the most important reasons is that the amount of resources required to eat locally grown foods rises to ever greater and more wasteful levels the more people eat locally grown foods simply because those foods are locally grown and, hence, the consumption of which is believed to be better for the environment than eating non-locally grown foods.